Resistance of organic materials and cable structures to marine biological attack

The increasing use of submarine telephone cable has resulted in the need for information on the performance of organic materials and cable structures under marine conditions. Recently, Bell Telephone Laboratories initiated a program to acquire fundamental data on the resistance of a wide range of organic materials, as well as immediately applicable engineering information. The present progress report describes the program which includes accelerated, laboratory-microbiological tests, as well as the acquisition of data from actual marine exposures. In biochemical oxygen demand-type tests conducted to date polyethylene was not utilized as a carbon source by marine bacteria. Polyvinyl chloride plastics served as a source of energy for the organisms depending on the way in which the materials were plasticized. Five elastomers were utilized by the bacteria. There has been a steady rise in capacitance values for GRS-insulated conductors exposed in sea water and sediment under laboratory conditions for thirteen months. These increases appear due to biological activity on the insulation. The general performance of materials undergoing marine exposure is reported including reference to penetration of a few synthetic materials by marine borers. Brief mention is made of the examination of submarine cable samples from service.